Juvenile case with the coexistence of maturity-onset diabetes of the young 1 and later-onset latent autoimmune diabetes in youth.

We present the case of a 12-year-old Japanese girl, who was positive for markers of both maturity-onset diabetes of the young and latent autoimmune diabetes in youth. She was initially diagnosed with maturity-onset diabetes of the young 1 based on the molecular analysis, and she later developed an autoimmune response, leading to β-cell-associated antibody-positive diabetes. She was treated with incretin-associated drugs and maintained adequate glycemic control. Pathophysiologically, there was an overlap between the two different types of diabetes, because the hyperglycemia and β-cell stress seen in non-autoimmune diabetes can cause β-cell autoimmunity over time.